2004 年中国植物科学若干领域研究进展

随着模式植物拟南芥(Arabidopsis thaliana)和水稻(Oryza sativa)基因组测序工作的完成, 国际植物科学的研究在近年来得到了极大的推动。我国植物科学领域也在整体上取得了重大进展, 特别是水稻基因组框架图(Yu et al., 2002)和4 号染色体基因组精细图(Feng et al., 2002)以及水稻控制分蘖的MOC1基因发现(Li et al., 2003)等重大研究成果在Science和Nature等国际顶级科技刊物上的发表, 使国际科学界对中国的科学研究水平刮目相看, 亦使中国科学家为之振奋。据不完全统计, 2004年中国科学家本土取得研究成果在植物科学专业顶级学术刊物The Plant Cell、The Plant Journal 和Plant Physiology 上发表的论文有2 2 篇, 在其他重要综合性期刊Nature、Science、PNAS、Trends in Plant Science、Molecular Biolgy and Evolution、Ecology Letters和Conservation Biology等上也有论文发表, 这反映了我国科研总体水平正在迅速提高。本文基于我国科学家发表在这些著名刊物上的成果对《植物学通报》的读者作一简单介绍, 希望从一些侧面反映我国科学家在本土所做研究的主要进展, 由于篇幅有限, 不能对每个领域各项逐一介绍, 收集文献不尽完善请同行和读者见谅。下面就不同研究领域举例作一介绍。     

2012年中国生物多样性研究进展简要回顾

中国的生物多样性研究在2012年取得了明显进展,在国际上的影响力不断提高.在生物多样性科学及相关领域比较好的国际刊物上发表的学术论文数量明显增加,质量也在提高(http://www.biodiversity-science.net/fileup/PDF/w2013-024-1.pdf).魏辅文研究组利用全基因组和深度测序的数据对旗舰种大熊猫的演化历史的解析(Zhao et al.,2012)、方精云及其团队在Ecography出版关于中国山地植物多样性格局的专辑、陈之端研究组命名的节蒴术科(Borthwickiaceae)被APG系统接受(Su et al.,2012)、何芳良提出根据分布面积的变化来评估物种灭绝风险的方法(He,2012)、邓建明等对植物自疏过程中密度与个体大小尺度关系的定最刻画(Deng et al.,2012a,b),以及余世孝等(Liu et al.,2012)和米湘成等(Mi et al.,2012)对群落谱系学方法的应用具有代表性.限于篇幅,本文仅从5个方面予以简单介绍.     

人类Y染色体长臂异染色质区与鱼类基因组的比较分析

脊椎动物有一些共同特征,这些共有性状都是在漫长的进化历程中保留下来的,因而极具保守性.这种进化上性状的保守性反映了它们的基因组结构存在一定的保守性.人类和硬骨鱼类在进化地位上相差甚远,正因如此,它们基因组之间的保守结构才真实代表了脊椎动物进化的最本质特征.因此,以斑马鱼( Dario rerio )和河豚等鱼类模式物种与人类之间直接开展比较基因组研究是近年来的国际学术探讨热点之一(Amores et al .,1998; Meyer et al .,1998).     

植物病原真菌附着胞的机械穿透力

植物病原真菌侵入寄主组织并在寄主组织中生长是其致病的基本条件(Deising et al., 2000; Hartmann et al.,1996; Tucker & Talbot, 2001; Buller,1931).但是,关于病原真菌是靠机械力还是酶解作用,亦或是二者结合穿透寄主的争论,已经持续了多年(Latunde-Dada,2001;Mendgen et al.,1996).许多植物病原菌能形成称为附着胞的特异侵染结构,可以产生很大的机械压力,推动侵染菌丝侵入寄主组织.顶端生长是菌丝生长的特点之一,通过顶端生长,可以侵入固体基质获取营养.真菌细胞内的渗透压是维持顶端生长、推动病原真菌侵入寄主的动力.早在1931年, Buller(1931)在一个简单的实验中已经观察到真菌菌丝细胞内巨大膨压的产生并转化为压力的现象:一种鬼伞Coprinus sterquilinus的菌柄直径仅有6mm,却可以撑起200g的重物,压强至少可达0.07 MPa (0.7 bar).许多蘑菇种类可以顶起障碍物及顶开沥青路面或石块等,都显示了菌丝的膨压可以使菌丝细胞产生很大的机械强度.最近关于稻瘟病菌Magnaporthe grisea的研究结果表明,病菌可以产生足够的机械力直接穿透水稻的表皮细胞(De Jong et al.,1997).本文对真菌穿透寄主的机械力的研究进展进行简述.     

论Mufushania三叶虫分类

通过对我国己经正式发表的Mufushania三叶虫的18个种模式标本的头盖特征进行Q型聚类分析,并结合传统定性分析后,提出其中Mufushania shalangensis Zhang and Zhou inZhang et al.,1980,M.angustilimbata Zhang and Zhou inZhang et al.,1980,和M.kailiensis(Yuan in Yuan et al.,2002)(=Elrathiella kailiensis Zhou in Lu et al.,1974)等3种应从Mufushania属中删除,对余下15个种,通过修订,转移和归并为2个种:M.nankingensis Lin,1965和M.bella(Yuan in Yuan et al.,2002)。本文将对研究我国寒武纪第二世晚期褶颊虫类三叶虫系统演化、生物地理分区以及华北与华南生物地层划分和对比,提供重要依据。     

Transposon-based screen identifies a XRE family regulator crucial for candicidin biosynthesis in Streptomyces albus J1074

正Dear Editor,Polyene macrolides are a group of natural products with potent antifungal activity (Caffrey et al., 2016). Candicidin/FR-008, a potent broad-spectrum anti-fungal agent, is produced by several Streptomycetes, including Streptomycetes sp. strain FR-008 (Chen et al., 2003), S. griseus 3570(Campelo and Gil, 2002) and S. albus J1074 (Olano et al.,2014). Due to its medical importance, considerable effort has been applied to elucidate its biosynthetic pathway and identify key regulatory genes (Chen et al., 2003; Zhang et al.,2015).     

Structural basis of AimP signaling molecule recognition by AimR in Spbeta group of bacteriophages

Dear Editor,Quorum sensing(QS)is a widespread phenomenon in bacteria which enables them to participate in cell-to-cell communication by producing and responding to small signal molecules,thus synchronously altering their behavior depending on population density(Singh et al.,2000;Miller and Bassler,2001).Through QS,bacteria coordinate processes such as expression of virulenee factors(Slamti and Lereclus,2002),biofilm formation(Parashar et al.,2011),sporulation(Perego et al.,1996),conjugation(Kozlowicz et al.,2006),antibiotic synthesis(Miller and Bassler,2001;Whiteley et al.,2017)etc.     

Bmelo12, an elongase of very long-chain fatty acids gene,regulates silk yield in Bombyx mori

<正>In silkworm, cocoon shell weight (CSW), an index of silk yield, is a quantitative trait (Nagaraju and Goldsmith, 2002), and multiple quantitative trait loci (QTLs) located on different chromosomes have been found(Zhan et al., 2009; Zhang et al., 2010; Li et al., 2015; Fang et al., 2020).     

Engrafted newborn neurons could functionally integrate into the host neuronal network

The limited capability to regenerate new neurons following injuries of the central neural system (CNS) still remains a major challenge for basic and clinical neuroscience.Neural stem cells (NSCs) could nearly have the potential to differentiate into all kinds of neural cells in vitro.Previous studies verified that exogenous transplanted NSCs are capable of differentiating into neurons and projecting onto the host neurons in the rat brain (Tabar et al.,2005;Dong JR et al.,2012),which could lead to behavioral recovery from neuronal damages such as spinal cord injury (McDonald et al.,1999),Parkinson's disease (Gonzalez et al.,2015;Kim et al.,2002;Lindvall,2001),and stroke (Zhang et al.,2016).     

哺乳动物细胞去核产物(胞质体及核体)的结构与功能研究

1967年Carter发现细胞松弛素可以诱发组织培养细胞的自发排核之后,Prescott(1972)借助细胞松弛素存在下的离心处理,使这一排核现象普遍化,从而确立了体外细胞去核的标准方法。经过不断改进(croce et al., 1974;Veomett et al., 1976;Lucas etal., 1976;Wigler et al., 1975),现在,这一技术已广泛应用于细胞学研究的各个重要领域(Mc Burney et al., 1979;Goldman et al., 1974;du Bols et al., 1980)。细胞去核技术及其应用的研究在我国已有初步开展(陈瑞铭等,1979;沈鼎武等,1980)。本实验对二种上皮型传代细胞系进行了去核手术,用扫描电镜和透射电镜对所获得的胞质体     

Role for dopamine in malonate-induced damage in vivo in striatum and in vitro in mesencephalic cultures

Defects in mitochondrial energy metabolism have been implicated in the pathology of several neurodegenerative disorders. In addition, the reactive metabolites generated from the metabolism and oxidation of the neurotransmitter dopamine (DA) are thought to contribute to the damage to neurons of the basal ganglia. We have previously demonstrated that infusions of the metabolic inhibitor malonate into the striata of mice or rats produce degeneration of DA nerve terminals. In the present studies, we demonstrate that an intrastriatal infusion of malonate induces a substantial increase in DA efflux in awake, behaving mice as measured by in vivo microdialysis. Furthermore, pretreatment of mice with tetrabenazine (TBZ) or the TBZ analogue Ro 4-1284 (Ro-4), compounds that reversibly inhibit the vesicular storage of DA, attenuates the malonate-induced DA efflux as well as the damage to DA nerve terminals. Consistent with these findings, the damage to both DA and GABA neurons in mesencephalic cultures by malonate exposure was attenuated by pretreatment with TBZ or Ro-4. Treatment with these compounds did not affect the formation of free radicals or the inhibition of oxidative phosphorylation resulting from malonate exposure alone. Our data suggest that DA plays an important role in the neurotoxicity produced by malonate. These findings provide direct evidence that inhibition of succinate dehydrogenase causes an increase in extracellular DA levels and indicate that bioenergetic defects may contribute to the pathogenesis of chronic neurodegenerative diseases through a mechanism involving DA.     

Scurvy in capybaras bred in captivity in Argentine

In order to determine if the absence of vitamin C in the diet of capybaras (Hydrochoerus hydrochaeris) causes scurvy, a group of seven young individuals were fed food pellets without ascorbic acid, while another group of eight individuals received the same food with 1 g of ascorbic acid per animal per day. Animals in the first group developed signs of scurvy-like gingivitis, breaking of the incisors and death of one animal. Clinical signs appeared between 25 and 104 days from the beginning of the trial in all individuals. Growth rates of individuals deprived of vitamin C was considerably less than those observed in the control group. Deficiency of ascorbic acid had a severe effect on reproduction of another population of captive capybaras. We found that the decrease in ascorbic acid content in the diet affected pregnancy, especially during the first stages. The results obtained suggest that it is necessary to supply a suitable quantity of vitamin C in the diet of this species in captivity.     

Changes in lactate dehydrogenase activity in chicken tissues in hyperthyreosis in ontogenesis

The lactate dehydrogenase activity in reactions of lactate oxidation and synthesis was studied in subfractions of the chicken brain, heart and liver at the embryonal, early postembryonal and adult stages of development after thyroxine administration. It has been shown that during embryogenesis thyroxine predominantly enhanced the rate of lactate oxidation in the mitochondrial tissues. A marked increase in the lactate synthesis was found in cytoplasm of the adult chicken tissues. Specificity of enzyme activity alterations was detected in the chicken brain during ontogenesis after thyroxine administration.     

SSTR5 ablation in islet results in alterations in glucose homeostasis in mice

Somatostatin (SST) peptide is a potent inhibitor of insulin secretion and its effect is mediated via somatostatin receptor 5 (SSTR5) in the endocrine pancreas. To investigate the consequences of gene ablation of SSTR5 in the mouse pancreas, we have generated a mouse model in which the SSTR5 gene was specifically knocked down in the pancreatic beta cells (betaSSTR5Kd) using the Cre-lox system. Immunohistochemistry analysis showed that SSTR5 gene expression was absent in beta cells at three months of age. At the time of gene ablation, betaSSTR5Kd mice demonstrated glucose intolerance with lack of insulin response and significantly reduced serum insulin levels. Insulin tolerance test demonstrated a significant increase of insulin clearance in vivo at the same age. In vitro studies demonstrated an absence of response to SST-28 stimulation in the betaSSTR5Kd mouse islet, which was associated with a significantly reduced SST expression level in betaSSTR5Kd mice pancreata. In addition, betaSSTR5Kd mice had significantly reduced serum glucose levels and increased serum insulin levels at 12 months of age. Glucose tolerance test at an older age also indicated a persistently higher insulin level in betaSSTR5Kd mice. Further studies of betaSSTR5Kd mice had revealed elevated serum C-peptide levels at both 3 and 12 months of age, suggesting that these mice are capable of producing and releasing insulin to the periphery. These results support the hypothesis that SSTR5 plays a pivotal role in the regulation of insulin secretion in the mouse pancreas.